These guns were fitted to many battleships and battlecruisers completed just before and after the start of World War I. When compared to contemporary British guns in terms of penetrating power, they were superior to the 12"/45 (30.5 cm) and 12"/50 (30.5 cm) guns, and only slightly less powerful than the 13.5" (34.3 cm) guns. They were, of course, completely outclassed by the 15"/42 (38.1 cm) guns used on the Queen Elizabeth class.

The battlecruisers Derfflinger and Lützow used these weapons at the Battle of Jutland (Skagerrak) to sink the British battlecruisers HMS Queen Mary and HMS Invincible.

The World War I Coastal Defense Battery Kaiser Wilhelm II located near Knocke in Belgium was equipped with four of these guns.

The mountings for these guns used electric pumps to drive hydraulic elevation gear while the training was all electric. These guns also had hydraulically worked rammers and breeches, the first fitted to German large-caliber guns. These changes increased the rate of fire, with most ships having a ROF of 20 seconds while the Kaiser class were reported to have had an overall ammunition supply speed of three rounds in 48 seconds, including all transfers.

In World War II these guns were used only as coastal artillery. They were then supplied with a more streamlined shell and used a larger propellant charge, giving them increased range. The best known battery was the six-gun Friedrich August at Wangerooge. Later, three of these guns on BSG mountings were moved to near Wimille on the Channel Coast.

Constructed from shrunk on tubes and hoops and used the Krupp horizontal sliding wedge breech block.

Actual bore diameter was 30.50 cm (12.008").

Gun Characteristics

Designation 30.5 cm/50 (12") SK L/50
Ship Class Used On Helgoland, Kaiser, König and Derfflinger Classes
Date Of Design 1908
Date In Service 1911
Gun Weight 114,309 lbs. (51,850 kg) 1
Gun Length oa 600.4 in (15.250 m)
Bore Length 569.3 in (14.461 m)
Rifling Length 465.0 in (11.805 m)
Grooves (88) 0.262 in D x 0.118 in W (6.68 mm D x 3.0 mm W)
Lands 0.165 in (4.20 mm)
Twist Increasing RH 1 in 45 to 1 in 30 at the muzzle
Chamber Volume For 551 lbs. (250 kg) shells: 12,052 in3 (197.5 dm3)
For 892.9 lbs. (405 kg) shells: 12,205 in3 (200.0 dm3)
Rate Of Fire 2 - 3 rounds per minute
  • ^The often-seen figure of 171,079 lbs. (77,600 kg) for this weapon actually includes the weight of the Weige (gun cradle).


Type Cartridge - Bag
Projectile Types and Weights 1a 2a World War I
    APC L/3,4: 892.9 lbs. (405.0 kg) 3a
    HE L/3,8: 892.9 lbs. (405.0 kg)) 3a 4a

World War II
    APC L/3,4: 892.9 lbs. (405.0 kg) 3a
    APC L/4,9 5a: 915 lbs. (415 kg)
    HE L/3,8 base fuze: 892.9 lbs. (405.0 kg) 3a

Special Coastal Artillery Projectile
    HE L/3,6 base and nose fuze 6a: 551 lbs. (250 kg)

Bursting Charge World War I
    APC L/3,4: 25.4 lbs. (11.5 kg)
    HE L/3,8: 58.2 lbs. (26.4 kg)

World War II
    APC L/3,4: 25.4 lbs. (11.5 kg)
    APC L/4,9: N/A
    HE L/3,8 base fuze: 59.5 lbs. (27.0 kg)
    HE L/3,6 base and nose fuze: 32.0 lbs. (14.5 kg)

Projectile Length World War I
    APC L/3,4: 40.8 in (103.7 cm)
    HE L/3,8: 48.38 in (122.9 cm)

World War II
    APC L/3,4: 40.8 in (103.7 cm)
    APC L/4,9: 58.8 in (149.5 cm)
    HE L/3,8 base fuze: 45.6 in (115.9 cm)
    HE L/3,6 base and nose fuze: 55.1 in (140 cm)

Propellant Charge 7a 8a World War I
    Fore Charge: 76 lbs. (34.5 kg) RPC/12
    Main Charge: 201 lbs. (91 kg) RPC/12

World War II (as of 1940)
   For APC L/3,4 and HE L/3,8
     Fore Charge: 93.7 lbs. (42.5 kg) RPC/32 (1230 x 16/6,7)
     Main Charge: 192.0 lbs. (87.1 kg) RPC/32 (1230 x 16/6,7)

   For HE L/3,6 base and nose fuze
     Fore Charge: 136.5 lbs. (61.9 kg) RPC/32 (1230 x 16/6,7)
     Main Charge: 188.3 lbs. (85.4 kg) RPC/32 (1230 x 16/6,7)

   Total main cartridge weight for RPC/32: 313 lbs. (142 kg) (1230 x 16/6,7)
   Silk bag for fore charge: 5.3 lbs. (2.4 kg)

After 1942 9a
    Full-weight shells: 268 lbs. (121.5 kg) RPC/38 (18/8)
    HE L/3,6: 315 lbs. (143 kg) RPC/38 (18/8)

Muzzle Velocity 10a World War I
    2,805 fps (855 mps)

World War II
    APC L/3,4: 2,805 fps (855 mps)
    APC L/4,9: 2,789 fps (850 mps)
    HE L/3,8 base fuze: 2,789 fps (850 mps)
    HE L/3,6 base and nose fuze: 3,675 fps (1,120 mps)

Working Pressure 20.9 tons/in2 (3,300 kg/cm2)
Approximate Barrel Life 200 rounds
Ammunition stowage per gun 11a Helgoland: 85 rounds
Kaiser: 86 rounds 12a
König 13a and Derfflinger 14a: 90 rounds
  • ^APC shells were painted blue, HE yellow and Training red. A black painted nose indicated that the shell was armed.
  • ^
    Actual designations for World War I Projectiles
    APC L/3,4 30,5 cm Psgr. L/3,4 (m.Hb)
    HE L/3,8 30,5 cm Spgr. L/3,8 Bdz

    Actual designations for World War II Projectiles
    APC L/3,4 30,5 cm Psgr. L/3,4 (m.Hb)
    APC L/4,9 30,5 cm Psgr. L/4,9 (m.Hb)
    HE L/3,8 base fuze 30,5 cm Spgr. L/3,8 Bdz
    HE L/3,6 base and nose fuze 30,5 cm Spgr. L/3,6 Bdz u. Kz (m.Hb)
  • ^ for both the APC L/3,4 and for the HE L/3,8 vary in many references. I have chosen to use the weight given in both M.Dv. Nr. 170,54 and in M.Dv. Nr. 234,6 and as stenciled on the projectiles shown in these documents which are all given as 405.0 kg (892.9 lbs.).
  • ^As the HE L/3,8 projectiles used a base fuze and a thick nose wall, they should be considered more equivalent to SAP rounds. These rounds were capable of penetrating 6 to 20 feet (2 to 6 m) through unarmored structures before detonating.
  • ^There is conflicting information about the APC L/4,9 projectile. Some references do not list it. It is noted in "Naval Weapons of World War Two" but not listed in M.DV.Nr. 234,6, which was issued in 1941. This projectile may have been manufactured after that date. It is possible that the APC L/4,9 was simply the APC L/3,4 with a longer ballistic cap which would have been a relatively simple change.
  • ^German HE Base and Nose Fuzed projectiles with ballistic caps had a rod between the nose of the shell and the fuze to improve performance when striking obliquely. See details on 12.7 cm SK C/34 datapage.
  • ^These guns, like most large caliber German guns of this era, used a "fore charge" which was propellant in a double bag silk case and a "main charge" which was propellant in a brass case. The brass case helped to seal the breech of the gun.
  • ^Propellant weights differ in many references and even in official documents such as the M.Dv. Nr. 170 and M.Dv. Nr. 190 series. This seems to be the result of most charges being listed as "zu etwa" which means "to about," implying that the propellant weights were not closely controlled and that differences of a kilogram or so were acceptable. In addition, different loading weights were used depending upon the powder grain size utilized to make up the charge. The weights in this table are for the powder grain specified.
  • ^I lack the break down between fore and main charges for the 1942 propellant charges.
  • ^Using the "Small Battle Load" of just the main charge gave a muzzle velocity of about 2,034 fps (620 mps).
  • ^Outfits were typically 70% APC and 30% HE.
  • ^British post-war documents claim that the Kaiser class carried 98 to 103 rounds per gun.
  • ^British post-war documents claim that the König class carried 96 to 100 rounds per gun.
  • ^Outfit for Derfflinger class was 65 APC and 25 HE per gun.
  • Diagrams of some of these projectiles and their fuzes and propellant charges may be found below.


World War I

Range of 892.9 lbs. (405.0 kg) APC L/3,4 1b
Elevation Distance
13.5 degrees 17,717 yards (16,200 m)
16.0 degrees 22,310 yards (20,400 m)

World War II

Range of 892.9 lbs. (405.0 kg) APC L/3,4 for coastal artillery batteries
Elevation Distance
45.0 degrees 35,000 yards (32,000 m)

Range of 915 lbs. (415 kg) APC L/4,9 for coastal artillery batteries 2b 3b
Elevation Distance
49.2 degrees 45,166 yards (41,300 m)
50.0 degrees 43,200 yards (39,500 m)

Range of 551 lbs. (250 kg) HE L/3,6 for coastal artillery batteries
Elevation Distance
49.1 degrees 56,200 yards (51,400 m)
  • ^See elevation note in the "Mounting / Turret" section below.
  • ^The data for the 915 lbs. (415 kg) APC L/4,9 shell is from two different sources, which may account for the large difference in range for only a slight change in elevation.
  • ^The APC L/4,9 shell had a significantly better ballistic shape than the previous ones. It is noted as being "of longer range" than the older APC, which I take to mean that the newer projectile would have had a longer range when fired at the same elevation.

Armor Penetration

Armor Penetration with 892.9 lbs. (405.0 kg) APC L/3,4
Range Side Armor Deck Armor
14,000 yards (12,800 m) 10.0" (254 mm) ---
16,000 yards (15,000 m) 9.0" (229 mm) ---

Data from "Jutland: An Analysis of the Fighting."

Armor Penetration with 892.9 lbs. (405.0 kg) APC L/3,4
Range Side Armor Deck Armor
10,940 yards (10,000 m) 13.6" (345 mm) ---
13,120 yards (12,000 m) 12.0" (305 mm) ---

Data from "German Battlecruisers of World War One."

Mount / Turret Data

Designation Two-gun Turrets
    Helgoland class (6): Drh LC/1908
    Kaiser class (5) 1c: Drh LC/1909
    König class (5) 2c: Drh LC/1911
    Derfflinger class (4): Drh LC/1912
    Hindenburg (4) 3c: Drh LC/1913

Single Coastal Artillery Turrets
    30.5 cm L/50 Kst.Drh.L.C/37

Weight Ships: Between 534 to 549 tons (543 to 558 mt) 4c 5c

Coastal Artillery: 271.9 tons (276.26 mt)

Elevation All ships as built: -8 / +13.5 degrees
After 1915: -5.5 to +16.0 degrees 6c

Coastal artillery: -5 / +50 degrees

Elevation Rate Ships: 4 degrees per second

Coastal Artillery: 10 degrees per second with shell loaded

Train End Turrets: About +150 / -150 degrees
Beam Turrets: About +80 / -80 degrees

Coastal Artillery: -220 / +220 degrees

Train Rate Ships: 3 degrees per second

Coastal Artillery: 4 degrees per second

Gun recoil 36.0 in (91.5 cm) 7c
Loading Angle Ships: about +5 degrees

Coastal Artillery: 0 degrees

  • ^The Kaiser class were the first German battleships to have superfiring turrets. This allowed them to have one less turret than previous classes (5 vs. 6) yet still be able to fire the same number of guns on the broadside.
  • ^The König class had all main guns on the centerline, giving them a heavier broadside than earlier ships.
  • ^Derfflinger had a crew of 70 men in C mounting and probably in A and B as well while D mounting had 80 crewmen.
  • ^The mounting weight differences were mainly the result of thicker armor used on the battleships.
  • ^
    Armor thickness given in "Naval Weapons of World War One" by Norman Friedman
    Battleships Battlecruisers
    Face 11.8 in (30 cm) 10.6 in (27 cm)
    Sides 9.8 (25 cm) 8.7 in (22 cm)
    Rear 11.4 in (29 cm) except Kaiser class: 10.6 in (27 cm) 10.6 in (27 cm)
    Roof 3.1 to 4.3 in (8 to 11 cm) except Helgoland class: 2.8 3.9 in (7 to 10 cm) 3.1 to 4.3 in (8 to 11 cm) except Hindenburg: 3.1 to 5.9 in (8 to 15 cm)
  • ^Prinzregent Luitpold was modified just before and the other ships shortly after Jutland (Skagerrak) to increase the maximum elevation from +13.5 to +16.0 degrees. A few sources claim that the maximum elevation was increased on all ships to 16.5 degrees rather than to 16.0 degrees. Norman Friedman in "Naval Weapons of World War One" gives conflicting data for maximum elevations and ranges with no explanation. For that reason, I do not believe this source to be a reliable reference in this matter.
  • ^The recoil distance given above is the nominal figure. The absolute, metal-to-metal recoil distance was 38.6 inches (98.0 cm).
  • Run out was by compressed air. Magazines were below shell rooms on the battleships.
  • On the Derfflinger class except for Hindenburg, A, B and C turrets had the magazines below the shell rooms, but D turret had the magazine above the shell room for reasons of space. D turret also did not have the shell hoists broken at the working chamber as did all other 30.5 cm (12") mountings. Instead, the projectile hoist ran directly from the shell room up to the gunhouse. Hindenburg had all shell rooms below the magazines as in the battleships. Hindenburg also differed from her half-sisters by having LC/1913 mountings with half the number of hoists as the the LC/1912, but these hoists ran faster and were still capable of supplying the equivalent of three complete rounds per gun per minute. The LC/1913 turrets had 7.7 m (25.5 foot) rangefinders on each turret rather than 3 m (10 foot) rangefinders on earlier designs. The Helgoland, Kaiser and König classes had a machinery level directly below the gunhouse with a handling room below it. Lower shell and projectile hoists came up to this room and the ammunition was then transferred over to upper hoists which ran up to the gunhouse. Battlecruisers were similar except for Hindenburg in which the projectile hoists ran directly up to the gunhouse although the propellant hoists were still two-stage.
  • Training of the gun turrets was electric and gun elevation was hydraulic. Hydraulic power was provided by two electrically-driven triple pumps. Rammers were hydraulically powered with fluid being supplied directly from the elevation pump. Wedge breech mechanisms were hydraulically powered but could be manually operated.
  • Propellant smoke was removed with two independent suction systems, each with its own motor. Should one motor fail, the other motor could be coupled to run both systems at a reduced rate.
  • For at least the Drh LC/1912 turrets, the guns were separated by a 25 mm (1.0") splinter bulkhead. Following the Dogger Bank action, German mountings were modified to improve flash precautions. Double flap doors were installed at the beginning and end of the cartridge hoist and ready ammunition was removed from the gun houses.
  • The gun axes were 106.3 in (270 cm) apart.

Additional Pictures

Special thanks to Peter Lienau for all of the following pictures.


"The Battle of Jutland" by Geoffrey Bennett
"Warship Special 1: Battle Cruisers," "Jutland: An Analysis of the Fighting" and "Naval Weapons of World War Two" all by John Campbell
"Battleship Design and Development 1905-1945" and "Naval Weapons of World War One" both by Norman Friedman
"German Warships 1815-1945" by Erich Gröner
"The Big Gun: Battleship Main Armament 1860-1945" by Peter Hodges
"The German Defenses on the Coast of Belgium" by Lt. Col. H.W. Miller USA in "The Journal of the American Society of Mechanical Engineers" Vol. 42, No. 6, June 1920
"North Sea Battleground: The War at Sea 1914-18" by Bryan Perrett
"Die Geschichte der deutschen Schiffsartillerie" by Paul Schmalenbach
"German Battlecruisers 1914-18" and "German Battlecruisers of World War One" both by Gary Staff
"German Warships of World War I" by John C. Taylor
"German Capital Ships of World War Two" by M.J. Whitley
"Merkbuch über die Munition der 30,5 cm SK L/50 der Marine-Küstenartillerie" M.Dv. Nr. 170,54 Berlin 1940, Oberkommando der Kriegsmarine
"Vorläufige Beschreibung der 28 cm S.K.L/45, 28 cm S.K.L/50 und 30,5 cm S.K.L/50 in Kst.Drh.L.C.37" M.Dv. Nr. 234,6 Berlin 1941, Oberkommando der Kriegsmarine
"Munitionsvorschriften für die Kriegsmarine - Panzersprenggranaten mit Haube - a) Psgr (m.Hb)" M.Dv. Nr. 190,1A1 by Oberkommando der Kriegsmarine
Special help from Peter Lienau and Thorsten Wahl

Page History

28 December 2008 - Benchmark
18 November 2010 - Corrected typographical error, modified some picture captions for clarity
26 August 2011 - Added twist and projectile information
21 December 2011 - Added picture of shell that hit HMS Defender
31 December 2011 - Added mounting notes and source for picture on Additional Pictures page
24 November 2012 - Added details on mountings
08 December 2014 - Added comment on HE shell weight, additional armor penetration data, additional information on mountings
29 August 2015 - Additional ammunition and mounting information
17 April 2016 - Corrected typographical error
02 March 2019 - Converted to HTML 5 format, reorganized notes and added sketch from M.Dv. Nr. 190,1A1